Project Summary This research proposal describes the development of a research program to study the biogenesis of Arabidopsis phytoalexins. We will begin by investigating the biosynthetic pathway of camalexin, a phytoalexin produced as part of the induced defense response. The first part of our two-phase plan for studying Arabidopsis phytoalexin pathways will focus on the identification of camalexin biosynthetic genes through a collaboration with the Ausubel lab at MGH. During this training period, I will attend relevant meetings and workshops, and I will consult regularly with three senior advisors to establish skills required for timely advance of the project. During the second, independent phase of the project I will biochemically characterize candidate phytoalexin pathway enzymes implicated by the data gathered during phase one. I expect that this work will serve as a springboard for the formulation of a new research program that uses a combination of genetics, chemistry, and biochemistry to elucidate secondary metabolite biosynthetic pathways in plants. A deeper understanding of these pathways will not only illuminate the molecular details of host-pathogen interactions, but it is also likely to have an important impact on human health, given the strong track record of plant natural products as clinically-used medicines.